Unit tests added for internal/config

internal/config/modify_test.go

@@ -0,0 +1,163 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/spf13/viper"
+)
+
+// useConfigFile points Viper at a new YAML config file holding contents.
+func useConfigFile(t *testing.T, contents string) string {
+	t.Helper()
+	resetViper(t)
+	path := filepath.Join(t.TempDir(), "config.yaml")
+	if err := os.WriteFile(path, []byte(contents), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	viper.SetConfigFile(path)
+	if err := viper.ReadInConfig(); err != nil {
+		t.Fatal(err)
+	}
+	return path
+}
+
+// readConfigFile reads path with a fresh Viper.
+func readConfigFile(t *testing.T, path string) *viper.Viper {
+	t.Helper()
+	v := viper.New()
+	v.SetConfigFile(path)
+	if err := v.ReadInConfig(); err != nil {
+		t.Fatal(err)
+	}
+	return v
+}
+
+func TestStoreValue(t *testing.T) {
+	tests := []struct {
+		key, value string
+		want       any
+		kind       reflect.Kind
+	}{
+		{"logging.level", "debug", "debug", reflect.String},
+		{"sources.sleeper.enabled", "true", true, reflect.Bool},
+		{"sources.fts_mock.api_root", "http://mock", "http://mock", reflect.String},
+		{"sources.fts_mock.interval", "30s", "30s", reflect.String},
+	}
+	for _, tt := range tests {
+		t.Run(tt.key, func(t *testing.T) {
+			path := useConfigFile(t, "logging:\n  level: warn\n")
+			conf := defaultConfig(t)
+
+			got, kind, err := StoreValue(&conf, tt.key, tt.value)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if got != tt.want || kind != tt.kind {
+				t.Errorf("got %#v <%s>; want %#v <%s>", got, kind, tt.want, tt.kind)
+			}
+			if v := readConfigFile(t, path).Get(tt.key); v != tt.want {
+				t.Errorf("file has %s = %#v; want %#v", tt.key, v, tt.want)
+			}
+		})
+	}
+}
+
+func TestStoreValueKeepsOtherKeys(t *testing.T) {
+	path := useConfigFile(t, "logging:\n  level: warn\n  file: /tmp/js.log\n")
+	conf := defaultConfig(t)
+	if _, _, err := StoreValue(&conf, "logging.level", "error"); err != nil {
+		t.Fatal(err)
+	}
+	v := readConfigFile(t, path)
+	if got := v.GetString("logging.file"); got != "/tmp/js.log" {
+		t.Errorf("logging.file = %q; want it kept", got)
+	}
+}
+
+func TestStoreValueErrors(t *testing.T) {
+	tests := []struct {
+		name, key, value, wantErr string
+	}{
+		{"unknown key", "nope", "x", ""},
+		{"section key", "sources", "x", ""},
+		{"bad bool", "sources.sleeper.enabled", "maybe", "expected <bool>"},
+		{"invalid log level", "logging.level", "shouty", "invalid log level"},
+		{"bad duration", "sources.fts_mock.interval", "eventually", "duration"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			path := useConfigFile(t, "logging:\n  level: warn\n")
+			before, _ := os.ReadFile(path)
+			conf := defaultConfig(t)
+
+			_, _, err := StoreValue(&conf, tt.key, tt.value)
+			if err == nil {
+				t.Fatal("expected an error")
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Errorf("err = %v; want it to mention %q", err, tt.wantErr)
+			}
+			if after, _ := os.ReadFile(path); string(after) != string(before) {
+				t.Errorf("config file changed:\n%s", after)
+			}
+		})
+	}
+}
+
+func TestStoreValueNoConfigFile(t *testing.T) {
+	resetViper(t)
+	conf := defaultConfig(t)
+	if _, _, err := StoreValue(&conf, "logging.level", "debug"); err == nil {
+		t.Fatal("expected an error with no config file to write")
+	}
+}
+
+func TestPurgeValue(t *testing.T) {
+	path := useConfigFile(t, "logging:\n  level: debug\n  file: /tmp/js.log\n")
+	conf := defaultConfig(t)
+
+	if err := PurgeValue(&conf, "logging.file"); err != nil {
+		t.Fatal(err)
+	}
+	v := readConfigFile(t, path)
+	if v.IsSet("logging.file") {
+		t.Errorf("logging.file still set: %v", v.Get("logging.file"))
+	}
+	if got := v.GetString("logging.level"); got != "debug" {
+		t.Errorf("logging.level = %q; want it kept", got)
+	}
+}
+
+func TestPurgeValueErrors(t *testing.T) {
+	path := useConfigFile(t, "logging:\n  level: debug\n")
+	before, _ := os.ReadFile(path)
+	conf := defaultConfig(t)
+
+	if err := PurgeValue(&conf, "nope"); err == nil {
+		t.Error("expected an error for an unknown key")
+	}
+	if after, _ := os.ReadFile(path); string(after) != string(before) {
+		t.Errorf("config file changed:\n%s", after)
+	}
+
+	resetViper(t)
+	if err := PurgeValue(&conf, "logging.level"); err == nil {
+		t.Error("expected an error with no config file to write")
+	}
+}
+
+func TestStoreValueUpdatesConf(t *testing.T) {
+	useConfigFile(t, "logging:\n  level: warn\n")
+	conf := defaultConfig(t)
+	if _, _, err := StoreValue(&conf, "sources.fts_mock.interval", "30s"); err != nil {
+		t.Fatal(err)
+	}
+	if conf.Sources.FTSMock.Interval != 30*time.Second {
+		t.Errorf("FTSMock.Interval = %v; want 30s", conf.Sources.FTSMock.Interval)
+	}
+}